hi every one i would like to set up the workspaces, so that the left one would be shown at the external monitor, and the right one would be displayed on the laptop.
but when i
plugged my monitor into laptop all what i see is a black screen in the laptop & nothing shows up in the external monitor

btw in earlier version of kali linux it works

i'm using : kali linux 2018.1 on a 32 bits pc
Linux root 4.15.0-kali3-686-pae #1 SMP Debian 4.15.17-1kali1 (2018-04-25) i686 GNU/Linux"